Teardown: Lite-On PS-2551-5L 550W Platinum CRPS Server PSU — Five Chemi-Con PSF Solid Capacitors on the 12V Rail
2026-09-22 · Compiled by Best IT Parts from public industry reporting
A teardown of Lite-On's PS-2551-5L, a 550W 80 PLUS Platinum server power supply in the CRPS-185 form factor, shows five Nippon Chemi-Con PSF series conductive polymer solid aluminum electrolytic capacitors on the output stage. Each of the five is rated 470µF/16V, for 2350µF of nominal output capacitance, and they are paired with four Chemi-Con KZE series 2200µF/16V long-life aluminum electrolytic capacitors to filter and buffer the high-current 12V rail.
The unit accepts 100-240V AC input as well as 240V HVDC, with a main rail rated 12V/45A and a separate 12V/3A standby output. Internally it uses a digital PFC front end, an LLC resonant converter and secondary-side synchronous rectification. Four Toshiba TPH2R306NH low-resistance MOSFETs perform synchronous rectification on the LLC transformer secondary, converting the high-frequency AC to 12V DC, which is then filtered by the output inductor and the capacitor bank.
The PSF series is rated for 20,000 hours at 105°C. Compared with conventional liquid aluminum electrolytic capacitors, polymer solid parts typically offer lower equivalent series resistance and higher ripple current handling, which suits the low-voltage, high-current output of a server supply. Paralleling five capacitors raises filtering capacitance while sharing ripple current and lowering overall ESR, which reduces self-heating.
The bank also releases stored energy during load steps, limiting output voltage sag when the server draws a sudden current surge, and absorbs excess energy when load drops or the synchronous rectifier generates high-frequency ripple. Working with the output inductor, the capacitors suppress ripple and high-frequency noise for the 12V feed to server motherboards, processors and storage devices.
Need this part in volume?
Best IT Parts supplies wholesale laptop power adapters, server power supplies and replacement parts, with OEM/ODM and private-label options.
Technical details are reproduced as reported. Verify specifications against the original source before design or procurement decisions.